Re: [PATCH v4 3/4] arm64: dts: qcom: shikra-cqm-evk: Enable display and add ili7807s panel

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] dts: backlight enable GPIO permanently asserted via pinctrl
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commit 00c4e0f47a97a648f49ab088ecacedb0603403a5
Author: Arpit Saini <arpit.saini@oss.qualcomm.com>

arm64: dts: qcom: shikra-cqm-evk: Enable display and add ili7807s panel

This commit enables the Shikra MDSS display subsystem on the Qualcomm Shikra
CQM EVK board and adds the DLC0697 MIPI DSI display panel node. It also
pins pm4125_l5 to 1.232V for DSI PHY PLL stability.

> diff --git a/arch/arm64/boot/dts/qcom/shikra-cqm-evk.dts b/arch/arm64/boot/dts/qcom/shikra-cqm-evk.dts
> index b112b21b1d79b..d9a0f32ce8d3b 100644
> --- a/arch/arm64/boot/dts/qcom/shikra-cqm-evk.dts
> +++ b/arch/arm64/boot/dts/qcom/shikra-cqm-evk.dts
[ ... ]
> +&mdss_dsi0 {
> +	vdda-supply = <&pm4125_l5>;
> +
> +	status = "okay";
> +
> +	panel@0 {
> +		compatible = "dlc,dlc0697", "ilitek,ili7807s";
> +		reg = <0>;
> +
> +		reset-gpios = <&tlmm 3 GPIO_ACTIVE_LOW>;
> +
> +		vddi-supply = <&pm4125_l15>;
> +		avdd-supply = <&vreg_disp_p>;
> +		avee-supply = <&vreg_disp_n>;
> +
> +		pinctrl-0 = <&panel_rst_n &panel_te_pin &panel_bl_en>;

[Severity: Medium]
Does mapping panel_bl_en in the default pinctrl state bypass the display
power management sequence?

The device core automatically applies this default state before calling the
panel's probe function. Since the panel driver (panel-ilitek-ili7807s) does
not natively acquire this GPIO nor implement runtime power management (PM),
the driver core will not switch to the sleep pinctrl state during DRM
unprepare (blanking).

> +		pinctrl-1 = <&panel_rst_n_suspend &panel_bl_en_suspend>;
> +		pinctrl-names = "default", "sleep";
> +
> +		port {
> +			panel_in: endpoint {
> +				remote-endpoint = <&mdss_dsi0_out>;
> +			};
> +		};
> +	};
> +};
[ ... ]
> +&tlmm {
[ ... ]
> +	panel_bl_en: panel-bl-en-state {
> +		pins = "gpio91";
> +		function = "gpio";
> +		drive-strength = <2>;
> +		bias-disable;
> +		output-high;
> +	};

[Severity: Medium]
Will this output-high configuration cause the backlight to remain permanently
powered on while the system is awake? 

Because the panel driver does not toggle this via runtime PM, this could 
result in a glowing black screen when the display is conceptually blanked
(DPMS off), wasting battery power. Could it also turn on the backlight too
early during boot before the panel driver has cleared the screen, causing
visual garbage?

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Sashiko AI review · https://sashiko.dev/#/patchset/20260916-shikra-dt-changes-v4-0-d5d5c3ffe070@oss.qualcomm.com?part=3